﻿/*
* Copyright (c) 2010-2012 Tesla Engine Group
* 
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
* 
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* 
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/


using System;
using System.Diagnostics;
using Tesla.Windows.Util;

namespace Tesla.Windows.Input {
    internal class MouseHook : IDisposable {

        private static IntPtr _hookID;
        private static MouseProc _proc = HookCallBack;
        private const int WH_MOUSE_LL = 14;

        private static int _mouseWheel = 0;

        internal static int CurrentWheel {
            get {
                return _mouseWheel;
            }
        }

        public MouseHook() {
            using(Process curProcess = Process.GetCurrentProcess())
            using(ProcessModule curModule = curProcess.MainModule) {
                _hookID = NativeMethods.SetWindowsHookEx(WH_MOUSE_LL, _proc, NativeMethods.GetModuleHandle(curModule.ModuleName), 0);
            }
        }

        ~MouseHook() {
            this.Dispose();
        }

        public void Dispose() {
            this.Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing) {
            NativeMethods.UnhookWindowsHookEx(_hookID);
        }

        private unsafe static IntPtr HookCallBack(int nCode, IntPtr wParam, IntPtr lParam) {
            if(nCode >= 0 && (MouseMessages) wParam == MouseMessages.WM_MOUSEWHEEL) {
                byte* ptr = (byte*) lParam.ToPointer();
                int num = *((int*) (ptr + 8)) >> 16;
                _mouseWheel += num;
            }
            return NativeMethods.CallNextHookEx(_hookID, nCode, wParam, lParam);
        }
    }
}